Field of the Invention
The invention relates to an electromagnet structure of an electric machine, in particular an adjustment drive of a motor vehicle. The electromagnet structure has a plurality of coils that are arranged in a circular structure.
Adjustment drives for motor vehicles, in particular power steering arrangements, are typically embodied in the form of an electric motor. Electric motors of this type are operated by way of a three-phase current. They comprise a fixed stator having an electromagnet structure that comprises a number of coils that are arranged as magnetic poles in a circular structure. The coils comprise in each case a coil winding and a connector that are produced from an electrically conductive material. The coil windings of the electromagnet structure are preferably in each case wound onto a coil body that is not electrically conductive. A rotor is arranged in a rotatable manner in the interior of the electromagnet structure, said rotor itself being provided with a coil winding or field winding in the case of a brushless electric motor having permanent magnets and in the case of a so-called commutator motor. If an electrical current flows through the phase windings that are formed by the stator-side coils, an exciter field that interacts with the magnetic field of the rotor is thus built up, as a result of which the rotor rotates about its rotor axis.
Generally, in each case, two of the coils are connected together as a coil pair, wherein a conductor track is electrically contacted by means of the respective connectors. In the case of a vibration of the electromagnet structure, it is possible for conductor bridges of coil pairs of different phases to make physical contact with one another in an electrically conductive manner. The phase connections that occur cause a malfunction of the electric motor and an undesired, safety critical, increased braking torque, in particular when steering in the case of power steering applications.
Generally, in order to avoid this phase connector problem, the conductor bridges are covered by a non-electrically conductive insulating tube of synthetic material. As a consequence, an additional production step is created when producing the stator system, which negatively influences the production costs and the duration of the production process of the stator system.